1. Field of the Invention
The present invention generally relates to ball and socket joint assemblies and more particularly relates to configurations that facilitate grease actuated adjustment of such assemblies.
2. Description of the Related Art
Ball and socket joint assemblies are useful in many applications, including connecting rod assemblies, steering knuckle and drag link assemblies used in vehicles, and for providing pivotal movement between tools and construction machines to which the tools are attached. FIG. 1 shows a conventional ball and socket joint assembly. Socket assembly 100 includes a generally cylindrical, hardened steel housing 110 welded to bracket 108 and defining a socket 109 in which a substantially spherical ball 140 may be disposed to form a joint. Socket assembly 100 also includes semicircular shims 112, 113, 114, 115, 116, 117 positioned flush against housing 110 adjacent to the inlet of socket 109. While only three (3) sets of shims are shown in FIG. 1, in many applications up to six (6) sets of shims are used. Shims 112-117 provide spacing between housing 110 and cap 130, which is tightened by bolts 131, 132, 133, 134, 135, 136 against housing 110 through shims 112-117. Both housing 110 and shims 112-117 define corresponding openings to receive bolts 131-136.
It is desirable in most applications to maintain a predetermined tolerance within the ball and socket joint. As ball 140 rotates within socket 109, both ball 140 and socket 109 wear to create excess space within socket 109. To account for this wear, socket assembly 100 is adjusted by removing pairs of shims 112-117 to re-establish a proper fit between ball 140 and socket 109. This adjustment is difficult to perform because it requires disassembly of socket assembly 100, including removal of bolts 131-136 and cap 130. This disassembly is further complicated by the fact that ball and socket joint assemblies are often positioned in hard to reach places in the vehicles and/or construction machines in which they are used. Consequently, the adjustment of socket assembly 100 is many times avoided.
Additional problems accompany the use of socket assembly 100. The use of multiple shims 112-117 cause bolts 131-136 to lose their torque during equipment operation. Grit and debris may build up on shims 112-117 over time. When bolts 131-136 are torqued onto housing 110, bolts 131-136 clamp cap 130 against housing 110, with shims 112-117 sandwiched in between. Subsequent vibration, however, may dislodge the debris on shims 112-117, thereby reducing the clamping forced applied by bolts 131-136. At a minimum, this requires more frequent adjustments to socket assembly 100, but may also result in damage to the equipment and/or safety concerns. Damage may also be caused to ball 140 and socket 109 if a machine operator removes too many shims 112-117 from socket assembly 100 during adjustment, thereby creating unwanted friction between ball 140 and socket 109. Additionally, because housing 110 of conventional socket assembly is made from hardened steel, difficulties are often encountered when attempting to weld housing 110 to other objects.